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Week3 Lecture Database Design
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Week3 Lecture Database Design


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  • Transcript

    • 1. Data Design Making sense of SQL.
    • 2. Database Design Principles.
    • 3. Database Design Principles. Know your technology and it’s limits.
    • 4. Database Design Principles. Know your technology and it’s limits. Collect all relevant information regarding your project’s data and plan, plan, plan.
    • 5. Database Design Principles. Know your technology and it’s limits. Collect all relevant information regarding your project’s data and plan, plan, plan. Only approach the computer once you have mapped out your database on paper.
    • 6. The technology Certain databases have limits, so know them. Microsoft Access 2 gigabyte Operating System sets the Microsoft SQL Server limit. Operating System sets the My SQL limit.
    • 7. The technology Databases can have a limit to the number of concurrent connections. Microsoft Access 255 users Microsoft SQL Server unlimited 125 by default My SQL unlimited once configured.
    • 8. The technology Databases have costs associated to them. Microsoft Access Can$300.00 Microsoft SQL Server $700 - $30 000 + My SQL free
    • 9. The technology Since the database is software, we have to ensure that we have powerful enough hardware to meet the demand of the service. Lots of users asking for data = Lots of power.
    • 10. Google Data Centre
    • 11. The technology Don’t paint yourself into a corner because of bad technology choices. Imagine the worst case scenario and PLAN FOR IT! MySQL can grow as long as there is hard drive space to handle the data files and servers fast enough to manage the traffic.
    • 12. Planning Your Database • Understand the data that you will be creating in the database and design entities. • An entity is a collection of objects (persons, places, things) described by the same attributes. • Entities are identified during the conceptual design phase of database and application design.
    • 13. Planning Your Database • Often the term entity is used instead of the word table. • A table in a database is where attributes are stored. • Attributes can be numbers, words, dates and even binary data objects. These are called the “data type” and are set on each attribute in the table.
    • 14. TABLE (or entity): tbl_myFriendsBirthdays Attribute Data Type Sample Data id integer 2 Name string Joe Birthday date/time 4082008 This table will store my friend’s birthdays. All of my friends have a name and a date of birth, so those ideas will become attributes. The complete collection of my friends attributes will become records in this table.
    • 15. Planning Your Database • Understand all of the data entities that you would ever want to store in the database. • Attempt to consider all available options and variations that your application is going to require.
    • 16. Exercise Let us pretend we are being asked to create an inventory database for a shoe company that manufactures different styles of footwear for different brands, like Nike. Let’s create a list of all related data that we would need to store regarding their inventory.
    • 17. Homework • Discover all of the data types that can be applied to attributes of a table (entity). • Print them onto a sheet of paper and bring this to next class. Please no copy and paste and have your name and the date on the sheet.